include/dmlite/c/io.h File Reference

C wrapper for I/O interfaces. More...

#include "dmlite.h"
#include "any.h"
#include "pool.h"
#include <sys/uio.h>
#include <unistd.h>

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Defines
#define	O_INSECURE   010
Typedefs
typedef dmlite_fd	dmlite_fd
Functions
dmlite_fd *	dmlite_fopen (dmlite_context *context, const char *path, int flags, const dmlite_any_dict *extra,...)
	Opens a file.
int	dmlite_fclose (dmlite_fd *fd)
	Closes a file.
int	dmlite_fstat (dmlite_fd *fd, struct stat *buf)
	Gets information about a file descriptor.
int	dmlite_fseek (dmlite_fd *fd, off_t offset, int whence)
	Sets the file position.
off_t	dmlite_ftell (dmlite_fd *fd)
	Returns the cursor position.
ssize_t	dmlite_fread (dmlite_fd *fd, void *buffer, size_t count)
	Reads from a file.
ssize_t	dmlite_fwrite (dmlite_fd *fd, const void *buffer, size_t count)
	Writes to a file.
ssize_t	dmlite_freadv (dmlite_fd *fd, const struct iovec *vector, size_t count)
	Reads from a file into multiple buffers.
ssize_t	dmlite_fwritev (dmlite_fd *fd, const struct iovec *vector, size_t count)
	Reads from a file into multiple buffers.
ssize_t	dmlite_fpread (dmlite_fd *fd, void *buffer, size_t count, off_t offset)
	Reads up to count bytes starting at the given offset. Does not change internal offset.
ssize_t	dmlite_fpwrite (dmlite_fd *fd, const void *buffer, size_t count, off_t offset)
	Writes count bytes starting at the given offset. Does not change internal offset.
int	dmlite_feof (dmlite_fd *fd)
	Returns 1 if EOF.
int	dmlite_ferrno (dmlite_fd *fd)
	Returns the last errror code.
const char *	dmlite_ferror (dmlite_fd *fd)
	Returns the last error message.
int	dmlite_donewriting (dmlite_context *context, const dmlite_location *loc)
	Finishes a PUT.
int	dmlite_fileno (dmlite_fd *fd)
	Returns the system file descriptor if available.

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Detailed Description

C wrapper for I/O interfaces.

Author:

Alejandro Álvarez Ayllon <aalvarez@cern.ch>

---

Define Documentation

#define O_INSECURE   010

Use this flag in addition to the standard ones to skip any security check (i.e. token validation)

---

Typedef Documentation

typedef struct dmlite_fd dmlite_fd

Handle for a file descriptor.

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Function Documentation

int dmlite_donewriting	(	dmlite_context *	context,
		const dmlite_location *	loc
	)

Finishes a PUT.

Parameters:

	context	The DM context.
	loc	The location as returned by dmlite_put.

Returns:

0 on success, error code otherwise.

int dmlite_fclose

(

dmlite_fd *

fd

)

Closes a file.

Parameters:

fd

The file descriptor as returned by dmlite_open.

Returns:

0 on success, error code otherwise.

int dmlite_feof

(

dmlite_fd *

fd

)

Returns 1 if EOF.

Parameters:

fd

The file descriptor.

Returns:

0 if there is more to read. 1 if EOF.

int dmlite_ferrno

(

dmlite_fd *

fd

)

Returns the last errror code.

Parameters:

fd

The file descriptor.

Returns:

The last error code.

const char* dmlite_ferror

(

dmlite_fd *

fd

)

Returns the last error message.

Parameters:

fd

The file descriptor.

Returns:

A pointer to an internal buffer with the last error message.

Note:

This buffer is specific to each file descriptor.

int dmlite_fileno

(

dmlite_fd *

fd

)

Returns the system file descriptor if available.

Parameters:

fd

The file descriptor.

Returns:

The file descriptor, -1 if it can not be retrieved.

Note:

Support depends on the plugin providing the file.

Calling dmlite_fclose _will_ close the file descriptor returned by this.

dmlite_fd* dmlite_fopen	(	dmlite_context *	context,
		const char *	path,
		int	flags,
		const dmlite_any_dict *	extra,
			...
	)

Opens a file.

Parameters:

	context	The DM context.
	path	The path to open.
	flags	See open()
	extra	The key-value pairs.
	...	Should be mode_t when called with O_CREAT.

Returns:

An opaque handler for the file, NULL on failure.

ssize_t dmlite_fpread	(	dmlite_fd *	fd,
		void *	buffer,
		size_t	count,
		off_t	offset
	)

Reads up to count bytes starting at the given offset. Does not change internal offset.

Parameters:

	fd	File descriptor.
	buffer	Buffer where to put the data.
	count	Number of bytes to read.
	offset	Read offset.

Returns:

Number of bytes actually read on success. -1 on failure.

ssize_t dmlite_fpwrite	(	dmlite_fd *	fd,
		const void *	buffer,
		size_t	count,
		off_t	offset
	)

Writes count bytes starting at the given offset. Does not change internal offset.

Parameters:

	fd	File descriptor.
	buffer	Data to write.
	count	Number of bytes to read.
	offset	Write offset.

Returns:

Number of bytes actually write on success. -1 on failure.

ssize_t dmlite_fread	(	dmlite_fd *	fd,
		void *	buffer,
		size_t	count
	)

Reads from a file.

Parameters:

	fd	The file descriptor.
	buffer	Where to put the data.
	count	Number of bytes to read.

Returns:

Number of bytes actually read on success. -1 on failure.

ssize_t dmlite_freadv	(	dmlite_fd *	fd,
		const struct iovec *	vector,
		size_t	count
	)

Reads from a file into multiple buffers.

Parameters:

	fd	The file descriptor.
	vector	Array of buffers.
	count	Number of elements in the array of buffers.

Returns:

Number of bytes actually read on success. -1 on failure.

int dmlite_fseek	(	dmlite_fd *	fd,
		off_t	offset,
		int	whence
	)

Sets the file position.

Parameters:

	fd	The file descriptor.
	offset	The offset.
	whence	See fseek()

Returns:

0 on success, error code otherwise.

int dmlite_fstat	(	dmlite_fd *	fd,
		struct stat *	buf
	)

Gets information about a file descriptor.

Parameters:

	fd	The file descriptor.
	buf	Where to put the information.

Returns:

0 on success, error code otherwise.

Note:

Not all plug-ins will fill all the fields, but st_size is a reasonable expectation.

off_t dmlite_ftell

(

dmlite_fd *

fd

)

Returns the cursor position.

Parameters:

fd

The file descriptor.

Returns:

The cursor position, or -1 on error.

ssize_t dmlite_fwrite	(	dmlite_fd *	fd,
		const void *	buffer,
		size_t	count
	)

Writes to a file.

Parameters:

	fd	The file descriptor.
	buffer	A pointer to the data.
	count	Number of bytes to write.

Returns:

Number of bytes actually written. -1 on failure.

ssize_t dmlite_fwritev	(	dmlite_fd *	fd,
		const struct iovec *	vector,
		size_t	count
	)

Reads from a file into multiple buffers.

Parameters:

	fd	The file descriptor.
	vector	Array of buffers.
	count	Number of elements in the array of buffers.

Returns:

Number of bytes actually read on success. -1 on failure.

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